Regioselective addition of nonsymmetrical monomers in radical polymerization is a basic issue for control of the reaction kinetics and structure of the resulting products. In reversible addition‐fragmentation chain transfer (RAFT) polymerization, head addition generates primary alkyl adducts when trapped by RAFT agents. Due to the low leaving ability of primary alkyl radicals, this kind of adduct in RAFT polymerization will become nonactive macro‐RAFT agents, that is, dead dormant species (DDS). Based on the previously‐developed equation for the correlation of DDS content (α) with head‐addition incidence (ρ₁) in RAFT polymerization and the quantitative determination method of DDS content by coupling a block‐polymerization derivatization with gradient polymer elution chromatography analysis, the ρ₁ values of methyl acrylate (MA) at different temperatures are determined with benzyl N‐carbazolecarbodithioate (BCBD) as RAFT agent and 2‐methyloxyethyl acrylate as the second monomer for block‐polymerization derivatization. The results show that the ρ₁ values of MA at 60, 70, 80, and 90 °C are 2.04 × 10⁻³, 2.37 × 10⁻³, 2.72 × 10⁻³, and 3.28 × 10⁻³, respectively, and the activation energy for ρ₁ is 15.8 kJ mol⁻¹. The DDS in BCBD‐mediated RAFT polymerization of MA is separated by column chromatography and characterized by ¹H‐NMR and MALDI‐TOF MS.

中文翻译：

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可逆加成-断裂链转移嵌段聚合衍生化和梯度聚合物洗脱色谱法测定丙烯酸甲酯的头部加成率和自由基聚合中的温度依赖性

在自由基聚合中非对称单体的区域选择性加成是控制反应动力学和所得产物结构的基本问题。在可逆的加成-断裂链转移（RAFT）聚合中，头部加成被RAFT剂捕获时会生成伯烷基加合物。由于伯烷基的低离去能力，RAFT聚合中的这种加合物将变成无活性的宏观RAFT剂，即死休眠种（DDS）。基于用于DDS的内容（α）与头加成发生率的相关的先前开发的方程（ρ ₁）的RAFT聚合和通过联接块聚合衍生化梯度聚合物洗脱色谱法分析DDS含量的定量测定方法，的ρ ₁N-咔唑碳二硫代苄基酯（BCBD）作为RAFT试剂和丙烯酸2-甲氧基乙基酯作为嵌段聚合衍生化的第二种单体，确定了不同温度下的丙烯酸甲酯（MA）值。该结果表明，ρ _1个在60 MA的值，70％，80％，和90℃是2.04×10 ^-3，2.37×10 ^-3，2.72×10 ^-3，和3.28×10 ^-3分别和为ρ的活化能₁是15.8千焦摩尔^-1。MA的BCBD介导的RAFT聚合中的DDS通过柱色谱分离，并通过¹ H-NMR和MALDI-TOF MS进行表征。